const fs = require('fs');

function addMapping(router,mapping){
    for (var url in mapping){
        if(url.startsWith('GET')){
            var path = url.substring(4);
            router.get(path,mapping[url]);
            console.log(`register URL mapping: GET ${path}`);
        }else if(url.startsWith('POST')){
            var path = url.substring(5);
            router.post(path,mapping[url]);
            console.log(`register URL mapping: POST ${path}`);
        }else{
            console.log(`invalid URL: ${url}`);
        }
    }
}

function addControllers(router){
    var files = fs.readdirSync(__dirname+'/controllers');
    var js_files = files.filter((f)=>{
        return f.endsWith('.js');
    });

    for(var f of js_files){
        console.log(`process controller: ${f}...`);
        let mapping = require(__dirname+'/controllers/'+f);
        addMapping(router,mapping);//API的处理函数
    }
}


module.exports = function(dir){
    let router = require('koa-router')();
    addControllers(router);
    return router.routes();
}